Abstract: Aiming at the thermal mismatch problem of dissimilar materials of segmented arc-heater, a new constrictor based on additive manufacturing was developed, which was fabricated by integrated molding of stainless steel. Based on the heat transfer analysis and numerical simulation, a simplified heat transfer model of the cooling flow field was established, a thermal structure optimization direction and method was proposed, and then the size and configuration of the new constrictor cooling structure were optimized. Finally, the arc heated jet test was carried out, which shows that additive manufacturing constrictor designed with optimization and reliability calculation could carry out test tasks for the corresponding state, in which surface heat flux was from 0 to 15.4 MW/m². However, its thermal efficiency is actually somewhat below the copper constrictor, and the average deviation is from 6.4% to 9.2%.